Viking SLAL - Manual (Page 8)

SECTION TSM 288 ISSUE A PAGE 8 OF 36
Integral pressure relief valves are normally used to protect the
pump from the effects of increases in system pressure caused,
for example, by a restricted or closed discharge line. In
response to a pressure increase the valve opens and internally
circulates the pumped media within the pump chamber.
When the valve opens, because the volume
of fluid circulating is relatively small, the
temperature of the fluid in the pump chamber
may rise if the pump continues to operate for
an extended period. In severe cases this may
result in temperatures in excess of the pumps
operating limits or vaporisation of the fluid, both
of which should be avoided. For these reasons
when the valve is activated the cause of the
system pressure increase should be eliminated
as continuous operation of the pump with the
valve open is not recommended and may cause
severe damage to the pump.
If the pump on which the valve is installed is to be installed
in either a pressurized system or one incorporating a vessel
under vacuum, the application of the valve should be referred
to Viking Pump or their authorized distributor.
The selection, setting and application of integral relief valves
is influenced by the viscosity and nature of the pumped media,
the pump operating speed and the required pressure relief
setting and mode of operation. For these reasons, and to cover
the diverse range of products, the conditions under which they
are pumped, and application demands, it is not practical to
factory set integral relief valves. The setting of the valve should
be carried out on site under the proposed duty conditions for
which the pump and valve were selected.
Before beginning the relief valve setting procedure
the pump should be installed, (see section 3.4)
with a pressure gauge in the discharge line
adjacent to the pump discharge port.
3.8.1 sETTING aNd OPERaTING
sPRING lOadEd ValVEs
See Figures 10, 11, 12 and 13.
• Remove cover (108). For integral relief valve with manual
lift, see Figure 11; first remove nut (129) and hand wheel
(111).
• Loosen nut (107) using a pry bar in the holes
provided, to relieve spring compression. For
integral relief valve with airlift, see Figure 13,
the air cylinder must be exhausted prior to
unscrewing the nut (107).
• Start pump, refer to section 3.5.
• Screw in nut (107) using pry bar in holes provided until
required pressure relief setting is reached.
NOTE: Care should be taken not to exceed the
lower of either the pumps maximum pressure
rating or the system design pressure.
• Reinstall cover (108). For integral relief valve with manual
lift, see Figure 11; reinstall hand wheel (111) and nut (129).
• The relief valve is now set.
3.6 sHUTdOWN PROCEdURE
After shutting the pump down close both the
suction and discharge valves and ensure that the
necessary safety precautions are taken:
• The prime mover power source has been
isolated.
• If installed, the pneumatically operated integral
relief valve has been depressurized.
• If installed, flushed product seal auxiliary
services have been isolated and de-
pressurized.
• Pump head and piping have been drained and
purged.
3.7 ROUTINE MaINTENaNCE
• SL Series pumps are shipped fully lubricated with a lithium
based extreme pressure lubricant suitable for sealed for
life units.
• For lubricant capacities refer to section 6.4.
3.8 INTEGRal PREssURE RElIEf
ValVEs
See Figures 10, 11, 12, 13, 14, and 15.
Most models in the SL Series series can be supplied with
integral pressure relief valves with both spring and air loaded
versions available. The function of the valves can be further
enhanced with the option of manual or airlift override offering
particular benefits where in-line cleaning is employed. Valves
incorporating this option can be opened to regulate the volume
of the cleaning media within the pump chamber thereby
avoiding the need for manual cleaning or external by-pass.
Where the pump is mounted onto a portable base plate
complete with motor and drive to be used as a mobile set, it
is strongly recommended that a integral pressure relief valve
is installed.
The SL Series integral pressure relief valves available include:
Spring Loaded - see Figure 10, 11, 12, & 13.
Valve can be set to required pressure relief setting.
Spring Loaded with Manual Lift - see Figure 11.
Valve can be set to required pressure relief setting. Manual lift
override can be used to open valve without disturbing pressure
relief setting.
Spring loaded with airlift - see Figure 13.
Valve can be set to required pressure relief setting. Airlift
override, which operates on an air supply of up to 7 Bar (105
psi) depending on pressure relief setting, can be used to open
valve without disturbing pressure relief setting.
Air loaded with airlift - see Figure 14.
Valve, which operates on an air supply of up to 7 Bar (100 psi)
for SLA - E, and 10 Bar (145 psi) for SLF, can be set to required
pressure relief setting. Airlift override, which operates on an air
supply of up to 7 Bar (100 psi) for SLA - E and 10 Bar (145 psi)
for SLF, depending on pressure relief setting, can be used to
open valve without disturbing pressure relief setting.
Air actuated relief valves can be operated remotely and
interfaced with other elements of the system or process
control.
WaRNING
WaRNING
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